Versions of add-apt-repository before 0.98.9.2, 0.96.24.32.14, 0.96.20.10, and 0.92.37.8ubuntu0.1~esm1, printed a PPA (personal package archive) description to the terminal as-is, which allowed PPA owners to provide ANSI terminal escapes to modify terminal contents in unexpected ways.
{
    "availability": "Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro",
    "binaries": [
        {
            "binary_name": "python-software-properties",
            "binary_version": "0.92.37.8ubuntu0.1~esm1"
        },
        {
            "binary_name": "python3-software-properties",
            "binary_version": "0.92.37.8ubuntu0.1~esm1"
        },
        {
            "binary_name": "software-properties-common",
            "binary_version": "0.92.37.8ubuntu0.1~esm1"
        },
        {
            "binary_name": "software-properties-gtk",
            "binary_version": "0.92.37.8ubuntu0.1~esm1"
        },
        {
            "binary_name": "software-properties-kde",
            "binary_version": "0.92.37.8ubuntu0.1~esm1"
        }
    ]
}
          {
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "python-software-properties",
            "binary_version": "0.96.20.10"
        },
        {
            "binary_name": "python3-software-properties",
            "binary_version": "0.96.20.10"
        },
        {
            "binary_name": "software-properties-common",
            "binary_version": "0.96.20.10"
        },
        {
            "binary_name": "software-properties-gtk",
            "binary_version": "0.96.20.10"
        },
        {
            "binary_name": "software-properties-kde",
            "binary_version": "0.96.20.10"
        }
    ]
}
          {
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "python3-software-properties",
            "binary_version": "0.96.24.32.14"
        },
        {
            "binary_name": "software-properties-common",
            "binary_version": "0.96.24.32.14"
        },
        {
            "binary_name": "software-properties-gtk",
            "binary_version": "0.96.24.32.14"
        },
        {
            "binary_name": "software-properties-kde",
            "binary_version": "0.96.24.32.14"
        }
    ]
}
          {
    "availability": "No subscription required",
    "binaries": [
        {
            "binary_name": "python3-software-properties",
            "binary_version": "0.98.9.2"
        },
        {
            "binary_name": "software-properties-common",
            "binary_version": "0.98.9.2"
        },
        {
            "binary_name": "software-properties-gtk",
            "binary_version": "0.98.9.2"
        },
        {
            "binary_name": "software-properties-qt",
            "binary_version": "0.98.9.2"
        }
    ]
}